Phillips and flat screwdriver
Use it for: To remove the handle screw, trim cap, or retaining parts.
Shop faucet screwdriversBathroom sink faucet repair
How to Replace a Bathroom Sink Hot Faucet Cartridge
If the bathroom sink only drips from the hot side, the hot handle is hard to turn, or the hot side will not shut off cleanly, replacing the bathroom sink hot faucet cartridge is often the right fix.
This is a moderate plumbing repair, but it is usually manageable for a careful homeowner. The main job is shutting off the water, removing the hot handle without damaging the trim, swapping in the matching cartridge, and testing for smooth operation and a full shutoff.
Before you start: Match the cartridge shape, stem pattern, and fixture compatibility before ordering.
Safety first
- Shut off the water before removing the handle or cartridge.
- Protect the sink drain so screws, clips, and trim pieces do not fall in.
- Use steady pressure instead of force when removing stuck handles or cartridges to avoid cracking trim or the faucet body.
- If a shutoff valve starts leaking when touched, stop and address that first.
Tools you may need
Adjustable wrench
Use it for: To loosen the retaining nut or bonnet if the faucet uses one.
Shop adjustable wrenches
Slip joint pliers
Use it for: To help remove stubborn retaining parts or pull the old cartridge carefully.
Shop slip-joint pliers
Allen key set
Use it for: Some faucet handles are held by a small set screw instead of a top screw.
Shop Allen key sets
Needle nose pliers
Use it for: To remove clips or grab small parts without dropping them.
Shop needle-nose pliers
Clean rag or towel
Use it for: To protect the sink finish, catch drips, and wipe mineral buildup from the valve body.
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Step-by-step fix
Step 1: Make sure the hot cartridge is the likely problem
- Confirm the leak, drip, or poor shutoff happens only on the hot side of the bathroom sink faucet.
- Turn the hot handle on and off a few times. A worn cartridge often feels stiff, gritty, loose, or fails to shut the water off fully.
- Check that the leak is coming from the spout or hot handle area, not from the supply line connections under the sink.
- Look at the cold side. If the cold side works normally and only the hot side acts up, the hot cartridge is a strong suspect.
If it works: You have a hot-side-only faucet problem that points to the hot cartridge.
If it doesn’t: If water is leaking from the supply line, shutoff valve, drain, or faucet body seam under the sink, fix that leak source first instead of replacing the cartridge.
Stop if:
- The faucet body is cracked, badly corroded, or loose in the sink deck.
- You cannot tell whether the leak is from the faucet internals or from a supply connection below the sink.
Step 2: Shut off the water and open the faucet
- Clear out the cabinet so you can reach both shutoff valves comfortably.
- Turn the hot and cold shutoff valves clockwise until they stop. Shut off both sides so the faucet cannot cross-feed while you work.
- Open the faucet to relieve pressure and confirm the water flow stops.
- Put a towel in the sink and over the drain opening so small screws or clips do not disappear.
If it works: The faucet is depressurized and safe to disassemble.
If it doesn’t: If one shutoff valve will not close fully, you may need to shut off the home's water before continuing.
Stop if:
- A shutoff valve leaks around the stem or sprays when you touch it.
- The shutoff valves are frozen in place and feel likely to break if forced.
Step 3: Remove the hot handle and retaining hardware
- Pry off the decorative cap if there is one, or locate the small set screw on the side or back of the hot handle.
- Remove the handle screw or loosen the set screw, then lift the hot handle off the stem.
- Take off any trim sleeve, bonnet, or retaining nut holding the cartridge in place.
- Lay the parts out in order on a towel so reassembly is straightforward.
If it works: The hot cartridge is exposed and ready to come out.
If it doesn’t: If the handle is stuck from mineral buildup, wiggle it gently and apply steady upward pressure rather than prying hard against the sink or trim.
Stop if:
- The handle or trim will only move with enough force that it may crack the sink, faucet body, or finished surfaces.
Step 4: Pull the old cartridge and match it to the replacement
- Remove any retaining clip, ring, or nut that locks the cartridge in place.
- Pull the cartridge straight out. If it is stuck, rock it gently while pulling so you do not gouge the valve body.
- Wipe out the valve opening with a clean rag and remove loose mineral debris.
- Compare the old and new cartridge side by side, checking overall length, stem shape, tabs, seals, and orientation marks.
If it works: The old cartridge is out and the replacement matches it closely.
If it doesn’t: If the new cartridge does not match the old one, stop and use the old cartridge as your reference for the correct replacement.
Stop if:
- The valve body is cracked, heavily pitted, or damaged inside.
- The replacement cartridge does not match the old one well enough to seat the same way.
Step 5: Install the new hot cartridge and reassemble the faucet
- Align the new cartridge the same way the old one sat in the valve body. Tabs and notches usually need to line up exactly.
- Push the cartridge fully into place without forcing it at an angle.
- Reinstall the retaining clip, ring, or nut, then snug it securely without overtightening.
- Reinstall the trim and hot handle, then tighten the screw or set screw until the handle feels secure.
If it works: The new cartridge is seated properly and the faucet is reassembled.
If it doesn’t: If the handle does not sit correctly or the retaining hardware will not thread smoothly, remove the cartridge and check its alignment again.
Stop if:
- The cartridge will not seat fully even though the valve body is clean and the part appears matched.
- Threads on the retaining nut or faucet body are stripped or cross-threaded.
Step 6: Turn the water back on and verify the repair holds
- Close the faucet, then slowly reopen the shutoff valves under the sink.
- Watch the faucet body, handle area, and supply connections for leaks as pressure returns.
- Run the hot water, then turn it off and wait a few minutes to confirm the drip is gone.
- Use the faucet several times in normal use to make sure the handle turns smoothly and the hot side shuts off cleanly every time.
If it works: The hot side operates smoothly, shuts off fully, and stays dry during real use.
If it doesn’t: If the faucet still drips from the hot side, remove the handle again and confirm the cartridge is the correct match and fully seated. If it still leaks after that, the faucet body or valve seat may be worn.
Stop if:
- Water leaks from inside the faucet body after reassembly.
- The faucet will not shut off after the new cartridge is installed.
Replacement Parts
Find a bathroom sink hot faucet cartridge on Amazon
Match the cartridge shape, stem pattern, and fixture compatibility before ordering.
As an Amazon Associate I earn from qualifying purchases. Repair Riot may earn a commission at no extra cost to you.
Verify the repair
- The hot handle turns on and off smoothly without grinding or sticking.
- The hot side stops fully with no drip from the spout after a few minutes.
- There are no leaks around the handle, trim, or under-sink shutoff area after restoring water.
- The faucet works normally through several on-off cycles in regular use.
FAQ
How do I know the hot cartridge is bad?
A bad hot cartridge often causes a drip from the spout only when the hot side is involved, a hot handle that feels stiff or rough, or a hot side that does not shut off cleanly.
Do I need to shut off both hot and cold valves?
Yes. Shutting off both sides helps prevent unexpected flow through the faucet while you have it apart.
What if the old cartridge is stuck?
Try gentle rocking and straight pulling after removing the retaining hardware. Mineral buildup commonly holds cartridges in place. Avoid twisting so hard that you damage the valve body.
Can I replace just the hot cartridge and leave the cold side alone?
Yes, if only the hot side is leaking or acting up. If both handles feel worn or both sides drip, replacing both cartridges may make sense while the tools are already out.
Why does the faucet still drip after I replaced the cartridge?
The new cartridge may be the wrong match, not fully seated, or installed in the wrong orientation. If those are correct, the faucet body or internal sealing surfaces may be worn.